Trende on Polarization

RealClearPolitics' Sean Trende writes something smart about political polarization in the U.S. See what he believes:

We have an ideologically polarized House and Senate because our country has become politically more polarized. The Grand Ideological Realignment that began in 1932, where we began substituting ideological parties for the old ethnic/sectional parties, has mostly worked its way out. Today, conservatives by and large vote for Republicans, and liberals by and large vote for Democrats.

It is perhaps difficult for younger readers to remember that this was not always the case. Here are two vivid examples. Until the mid-1960s, Southern Democrats were in fact conservatives in every sense of the word. And Earl Warren, Chief Justice of the very liberal "Warren Court" was a former Republican governor of California, appointed to the court by Republican President Eisenhower.